A wiper arm provided in a wiper device generally includes an arm head linked to a driving means and a retainer supporting a wiper blade and is configured by rotatably coupling the retainer to the arm head. Such an arm head is often composed of an arm head body coupled to the driving means and a cover member attached to the arm head body. With this construction, when a driving shaft of the driving means is fixed to the arm head body by a fixing member such as a nut, the fixing member can be hidden by the cover member.